Low density dynamite composition



Patented Feb. 26, 1935 LOW DENSITY. DYN

u'rn oo rosrrroN Harold A; Lewis, Wocdbury, N. J., assignor to air.

du Pont de Nemours & Company,.Wilnungton, DeL, a corporation of Delaware No Drawing. Application December 22, 1931, Serial No. 582,648

11 Claims. (01. 52-11) This invention relatesto an improved dynamite composition, and more particularly to such a composition comprising an explosive ingredient as sensitizing-agent and treated sunflower stalks as a new carbonaceous combustible ingredient of dynamite. V

Low density dynamites have become of particular importance in recent years. The, advantage of these explosives is, great in the blasting of materials having relatively low resistance, such as coal, salt, and soft rock for example. Since they allow v the distribution of strength of the explosive over considerable borehole wall surface, undue shattering of the material being blasted is thereby prevented The prior art discloses fully these and the numerous other advantages of low density dynamite compositions of the several types.

The prior art discloses also several means which have been employedin the production of low density dynamites in the past. For example, va-' rious carbonaceous combustible ingredients such as balsa wood, bagasse pith, ground cornstalks, ground popcorn, and the like, have been used, and have proved to be very satisfactory.

The object of this invention is to provide low density dynamites containing an improved combustible ingredient having, in addition to its low density properties, the advantages of low absorption value for liquid explosive ingredients, ready availability, and low cost.

I have discovered that the objects of this invention can be obtained by the incorporation in dynamite compositions of an improved carbonaceous material, namely treated sunflower stalks.

By the term sunflower I mean to designate all the species of genus Helianthus. The best known representative of this genus is the common sunflower, Helianthus annuus. Another suitable variety of this genus is Helianthus tuberosus, commonly known as the Jerusalem artichoke, this variety being a preferred type because of the valuable inulin bearing tubers which are obtained as a byproduct. By the term treated sunflower stalks is meant the product of any of several methods of preparing the sunflower stalks for incorporation in dynamite compositions. For example, these methods may consist simply of grinding, cutting, or otherwise disintegrating the stalks into a product of the desired fineness, or the disintegrated material may be suitably screened with the object of removing a portionor all of-the higher density fibrous material comprising the outside of the sunflower stalk, or the disintegrated material either screened or uning straight dynamites, and are used for general .nitrostarch dynamites.

'screened may be treated with water at elevated temperatures'in order to lower its flnaldensity,

and to remove water soluble materials. The treated material obtained by these several methods will have a density varying usually between 5 0.09 and 1. 13. V,

, My invention is applicable to all non-gelatinous types of explosive compositions, whether or not they contain a liquid explosiveingredient. The three main classes or" those containing liquids are 10 commonly known as straight dynamites, ammonia or extra dynamites, and permissible dynamites. The straight dynamites are commonly produced in several strengths varying from about 20% to about 75% and are used for various kinds of blasting, as priming agent for gelatinous explosives, in special Work in which, among other things, high velocity and sensitiveness to detonation is essential. These compositions usually comprise a liquid explosive ingredient in per- 0 centage equal to their grade strength, combustible absorbents, and sodium nitrate. The ammonia or extra dynamites are likewise made in several strengths ordinarily equivalent to the correspondblasting operations. They usually comprise a lower percentage of liquid explosive than the grade strength, ammonium nitrate, sodium nitrate and combustible absorbents; for example, the 20% strength powder may have 10% to 15% of liquid explosive and 8% to 15% of ammonium nitrate, and the strength powder may have 25% to 30% of liquid explosive and d5% to 55% of ammonium nitrate. The permissible dynamites are usually of high grade strength, from 40% to and are primarily for use in coal mines in which operations there exist the danger of explosions of dust and gas. Usually these dynamites contain relatively low percentages of liquid explosive, from about 8% to 15%, and relatively high percentages of ammonium nitrate, about 60% to combustible absorbents, and, in many cases inorganic salts adapted to the reduction of flame temperatures, such as sodium nitrate or sodium chloride. 45

By the term dynamite, as understood in the art, there are included such blasting explosive compositions that contain liquid explosive ingredients, such as nitroglycerin, nitroaromatic compounds, or a sensitizing ingredient such as nitrostarch.

Among the dynamite compositions containing no liquid explosive ingredient are those in which solid sensitizers are used, as for example, the

Per cent Per cam Per cent N itroglycerin 10 23 Ammonium nitrate.-- 52 Sodium nitratenun 5 2O 14 Treated sunflower stalks. 8 5 2 Other combustible 2 l5 9 It will, of course, be apparent from the foregoing that I can vary the percentages of materials shown in these examples quite widely and can introduce other ingredients not mentioned without departing from the spirit of my invention.

For example, I may use nitroglycerin or nitro glycol or mixtures thereof, with or without partial substitution of tetranitrodiglycerin, nitrated sugars, nitrocompounds, and the like. I may also increase the proportion of sodium nitrate appreciably, or I may'decrease the proportion or omit it'entirely, in which case I may use sodium chloride. Likewise, I may use along with treated sunflower stalks, both high density combustibles, such as corn meal, ivory nut meal, flour, or the like, and low density carbonaceous materials, such as bagasse pith, cornstalks, or the like.

By means of this invention it is possible to produce straight and ammonia dynamites weighing less than 181 grams per 1 x 8" cartridge, and in the case of dynamites of the permissible type this new ingredient makes it possible to obtain weights of 1%; x 8" cartdidges of less than 146 grams.

I claim:

1. A dynamite composition characterized by its low density which comprises a liquid explosive ingredient and disintegrated sunflower stalks.

2. A dynamite composition characterized by its low density which comprises disintegrated sunflower stalks and more than 6% plosive ingredient.

3. A dynamite composition characterized by its low'density which comprises a liquid explosive of liquid exingredient and at least 1% of disintegrated sunflower stalks. r

4. An explosive composition of the permissible type characterized by its low density which comprises a liquid explosive ingredient, ammonium nitrate, a non-explosive salt adapted to reduce flame temperature, and disintegrated sunflower stalks.

5. An explosive composition of the permissible type which comprises a liquid explosive ingredient, ammonium nitrate, a non-explosive salt 1 adapted to'reduce flame temperature, and disintegrated sunflower stalks, said composition having a density such that a 1%." x 8" cartridge weighs less than 146 grams.

6. An explosive composition of the straight dynamite type characterized by its low density which comprises a liquid explosive ingredient, sodium nitrate, and disintegrated sunflower stalks. V

7. An explosive composition of the straight dynamitetype which comprises a liquid explosive ingredient, sodium nitrate, and disintegrated sunflower stalks, said composition having a density such that a 1 x 8 cartridge weighs less than 181 grams.

8. An explosive composition of the ammonia type characterized by its low density which comprises a liquid explosive ingredient, ammonium nitrate, sodium nitrate and disintegrated sunflower stalks.

9. An explosive composition of the ammonia type which comprises a liquid explosive ingredient, ammonium nitrate, sodium nitrate, and disintegrated sunflower stalks, said composition having a density such that a 1%" x 8 cartridge weighs less than 181' grams.

10. A dynamite composition characteried by its low density which comprises a liquid explosive ingredient and 1 to 20% of disintegrated sunflower stalks.

11. A dynamite composition which comprises more than 6% of liquid explosive ingredient and more than 1% of disintegrated sunflower stalks, said composition having a density such that a 1 x 8" cartridge weighs less than 181 grams.

HAROLD A. LEWIS. 

